Fibre composite hybrid components

ABSTRACT

The invention relates to hybrid components comprising at least one fibre composite material as material B and at least one material A. Material A is selected from plastics, metals, ceramic compositions, wood, glass, composite materials, textile fibres and from prefabricated products produced from textile fibres. Material A is bonded to material B by at least one coating of an adhesion promoter composition comprising at least one copolyamide-based hotmelt adhesive.

The present invention relates to hybrid components, to processes for production thereof and to the use thereof, and to the use of adhesion promoter compositions.

Prior art hybrid components made from plastic and metal are components used inter alia in motor vehicle construction and in aircraft construction and also in electronics and electrical engineering and also in the sport and lifestyle sectors in the field of loadbearing parts and of parts that absorb forces, or as part of the housing, for example for decorative purposes. A particular feature of these is that they comprise local reinforcement systems which give the component particular mechanical properties and/or provide the possibility of functional integration. A feature requiring particular emphasis is increased component stiffness with additional weight reduction in comparison with components hitherto used in a conventional mode of construction.

The abovementioned application sectors increasingly use hybrid components in order to reduce mass and at the same time obtain optimized mechanical properties. The disadvantage of these hybrid components is lack of, or inadequate, adhesion between metal and plastic. Mechanical methods have therefore hitherto been used to anchor the plastic to the metal.

Adhesion between metal and plastic can be improved by using adhesion promoters. EP-A-1808468 and EP-A-2435246 disclose hybrid components where the bond between metal and plastic uses hotmelt adhesives in the form of copolyamide-based adhesion promoters additionally comprising isocyanate groups and epoxy groups.

The continuing trend toward ever more lightweight structures with equal or increased stiffness is leading to enhanced use of thermoplastic fibre composite materials (“composites”) within the established plastic and/or metal structures.

In the case of fibre composite materials too, typically form- and/or force-fitting connecting elements are made, for example through-moulding points, insert moulding operations, rivets, screws, “hedgehog” structures (for example T-Igel) etc.

The disadvantage of form- and/or force-fitting connecting elements with respect to cohesive elements is the local limitation on introduction of forces. Moreover, the required apertures in the material affect absorption and distribution of forces.

Improved transmission and introduction of forces between materials can be accomplished through cohesive bonds. It is possible here to dispense with apertures in the material, which weaken it, as necessary, for example, for form-fitting. However, a cohesive bond between fibre composite materials and a plastic can be established in injection moulding only in the case of like or particularly compatible material combinations, which greatly limits the selection of potential bonding partners. The is quality of the bond depends crucially on the process conditions used (temperature, time and pressure). Alternatively, a cohesive bond can be created by welding or by means of a suitable adhesion promoter, for example one based on polyurethane.

The problem addressed by the present invention was therefore that of providing a hybrid component which comprises at least one fibre composite material and is obtainable by cohesive bonding. In this way, a particularly high adhesion should be achieved between the respective, typically unlike materials. A hybrid component having increased stiffness and/or reduced weight combined with adhesion at least to nearly as high a level as compared with the known hybrid components composed of metal and plastic was to be obtained.

A bond between like partners is, for example, a bond between nylon-12 and nylon-12 or steel and steel. By contrast, a bond between unlike partners is, for example, the combinations of steel and aluminium, steel and nylon-6 or nylon-12 and nylon-6. The terms “unlike” and “like” are known to those skilled in the art.

It has been found that, surprisingly, coating with an adhesion promoter composition leads to the possibility of cohesive bonding of the fibre composite material to materials A to obtain a hybrid component.

The present invention accordingly provides a hybrid component comprising at least one fibre composite material as material B and at least one material A, wherein material A is selected from plastics, metals, ceramic compositions, wood, glass, composite materials, textile fibres and prefabricated products produced from textile fibres. The materials are bonded to one another by at least one coating of an adhesion promoter composition, wherein the composition comprises at least one copolyamide-based hotmelt adhesive.

Fibre composite materials as material B and materials A are referred to collectively hereinafter as materials.

Composite materials may include particulate composite materials, fibre composite materials, laminate composite materials (laminates), penetration composite materials and structural composite materials. The materials in a material composite may be polymeric, metallic, ceramic or organic.

Particulate composite materials are regarded as being, for example, grinding discs (ceramic particles in a polymeric or glass matrix), cemented carbide (ceramic particles in a metallic matrix), ceramic composites (ceramic particles in a ceramic matrix), fibreboards (organic particles in polymeric matrix), concrete (ceramic particles in ceramic matrix) or polymer concrete (mineral particles in polymeric matrix).

The matrix is the material in the composite material into which the other constituents are embedded.

Fibre composite materials in the context of the invention are, for example, glass fibre-reinforced glass, metal matrix composites (MMCs), fibre cement, carbon fibre-reinforced silicon carbide, fibre-plastic composites or fibre-ceramic composites (CMCs). Preferred fibre composite materials both as material A and as material B are fibre-plastic composites.

The laminate composite materials include composite sheets, composite tubes, TiGr composites (material composed of titanium, carbon fibres and epoxy resin), glass fibre-reinforced aluminium, sandwich sheets with a honeycomb core, bimetals and Hylites.

Preferred materials A are plastics, metals and fibre composite materials. Accordingly, hybrid components are preferably composed of fibre composite material, more preferably fibre-plastic composites, as material B and a material A selected from plastics, metals and fibre composite materials, more preferably fibre-plastic composites.

If both material A and material B are a fibre-plastic composite, material A may be the same as material B or different.

The hybrid component of the invention, comprising the adhesion promoter composition, material A and material B, may additionally be bonded to one or more materials C which may be the same as material A or different. The other materials C may have been bonded to the hybrid component of the invention by means of a form-fitting, force-fitting or cohesive bond, and it is optionally possible here to use an adhesion promoter composition.

Material C may be selected from plastics, metals, ceramic compositions, wood, glass, composite materials, textile fibres and prefabricated products produced from textile fibres. Preferred materials C are plastics, metals and fibre composite materials.

By appropriate preliminary tests, it is possible for the person skilled in the art to determine whether an adhesion promoter composition seems necessary for bonding of the hybrid component of the invention to further materials, such that optimal adhesion properties are obtained.

The invention further provides a process for producing an above-described hybrid component. In this case, the adhesion promoter composition is at least partly applied to or laid onto at least one of materials A and/or B, and materials A and B are bonded to one another. The adhesion promoter composition (also referred to hereinafter as composition) can be applied to one of the materials over the full area or part of the area.

To the extent that a material C is used for the production of an extended hybrid component, it is possible to begin by producing a hybrid component consisting of materials A and B. Subsequently, material C can be applied or laid on analogously to the methods for materials A and B and bonded to the hybrid component composed of A and B. Alternatively, materials A, B and C may be bonded together (in one step) for production of the extended hybrid component.

During the production of the hybrid component or of the extended hybrid component it is possible to combine various manufacturing steps such as moulding or forming processes, or machining, and to carry out these in a single process step (integrated manufacture). If plastic as material B is to be bonded to material A, preference is given to forming of the plastic and moulding of material A.

The compositions may be applied or laid on as a film. The application can be effected continuously or batchwise by means of electrophoretic enamelling, electrostatic spray processes, fluidized bed sintering, roll processes (for example coil coating), casting, jet processes and spraying, bar coating, brush coating, lamination, (hot) pressing, (co)extrusion or injection moulding, preference being given here to spray processes and roll application processes. The compositions here can be applied on one or both sides, locally or over the entire area. The stoved layer thicknesses (dry layer thicknesses) of the adhesion promoter compositions may be from 10 to 1000 μm, preferably 20 to 250 μm, and more preferably 30 to 150 μm. Preferred layer thicknesses in roll processes are from 5 μm to 250 μm, especially 10 μm to 50 μm.

The material with the applied adhesion promoter composition can be crosslinked and/or dried thermally, advantageous object temperatures here being from 120° C. to 240° C., preferably 150° C. to 225° C., more preferably 175° C. to 200° C., for a period of from 0.5 min to 30 min, preferably 1 min to 20 min, more preferably 3 min to 10 min. The person skilled in the art can determine suitable time/temperature conditions via preliminary tests. In roll processes, preferred peak metal temperatures (PMT) are from 180° C. to 240° C. The person skilled in the art will set the system or belt speed accordingly so as to achieve the PMT.

The compositions are thus cured thermally.

Preferred hybrid components are obtained as follows:

-   -   A) The metal (material A) coated with the composition is bonded         to the fibre composite material (material B) or     -   B) the fibre composite material (material B) coated with the         composition is bonded to the plastic (material A) or     -   C) the fibre composite material (material B) coated with the         composition is bonded to the metal (material A) or     -   D) the plastic (material A) coated with the composition is         bonded to the fibre composite material (material B) or     -   E) the fibre composite material (material A) coated with the         composition is bonded to a fibre composite material (material         B).

In variants A to E, fibre-plastic composites are particularly preferred fibre composite materials. The preferred hybrid components can be extended to include the materials C.

Variant A

The fibre composite material (for the composite composed of fibre composite material and metal) may be applied to the metal, for example, by extrusion, pultrusion, pressing, laminating, tape laying, winding, injection moulding or direct melt impregnation, and the fibre composite material may be bonded physically and/or chemically to the metal. Contact of the fibre composite material with the coated metal surface produces a cohesive bond and adhesion between the components.

Variant B

The plastic (for the composite composed of fibre composite material and plastic) may be applied to the fibre composite material, for example, by an injection moulding process including injection-compression moulding, by extrusion or by hot pressing, and the fibre composite material may be bonded physically and/or chemically to the plastic. Injection moulding technology is preferably used to inject the plastic. For this purpose, the coated fibre composite material part is inserted into the injection mould and, after closing of the mould, is coated in the mould with the plastic. Contact of the plastics melt with the coated fibre composite material surface produces a cohesive bond and adhesion between the components. The cohesively bonded component can then be demoulded from the injection mould and subjected to further processing or further mechanical operations.

Variant C

The metal (for the composite composed of fibre composite material and metal) may be applied to the fibre composite material, for example, by pressing, and the metal may be bonded to the fibre composite material and/or bonded by chemical means. Contact of the metal with the coated fibre composite material surface produces a cohesive bond and adhesion between the components.

Variant D

The fibre composite material (for the composite composed of fibre composite material and plastic) may be applied to the plastic, for example, by extrusion, pultrusion, pressing, laminating, tape laying, winding, injection moulding or direct melt impregnation, and the fibre composite material may be bonded physically and/or chemically to the plastic. Contact of the fibre composite material with the coated plastic surface produces a cohesive bond and adhesion between the components.

Variant E

One fibre composite material (for the composite composed of fibre composite material and fibre composite material) may be applied to the other fibre composite material, for example, by extrusion, pultrusion, pressing, laminating, tape laying, winding, injection m moulding or direct melt impregnation, and the two fibre composite materials may be bonded physically and/or chemically. Contact of one fibre composite material with the coated surface of the other fibre composite material produces a cohesive bond and adhesion between the components.

By virtue of the cohesive bond between the fibre composite material as material B and material A it is possible to achieve markedly advantageous force distribution and consequently to produce a stiffer overall design of the hybrid component. In addition, it is possible to save on costs and time in the production.

Another advantage resulting by virtue of the cohesive bond is weight reduction, since the improved transmission and introduction of forces enables use of a smaller amount of plastic or metal than in the case of form- or force-fitting bonds.

The combination of material B and material A and optionally material C can then be subjected to a heat treatment for from 2 min to 90 min, preferably from 5 min to 60 min, at from 120° C. to 240° C., in order to increase bond strength and degree of crosslinking. Hybrid components produced in this way have a durable bond between the material coated with the composition and the plastic or the fibre composite material, and exhibit high mechanical and dynamic strength.

The invention further provides for the use of the hybrid components of the invention as structural components or lightweight components, or components having surface or protective functions. The hybrid components may additionally assume decorative functions.

The resultant hybrid components may be used as a semi-finished product in the form of sheets or profiles for further processing to give components. These include, for example, sandwich sheets comprising at least three layers, of which the two outer layers may be the same or different. Sandwich sheets may have, for example, a fibre composite material core and outer metal layers.

The hybrid components may be used in mechanical engineering and plant construction, as seats in motor vehicles or aircraft, shock absorbers, bodywork and chassis parts such as front-end bearings, door, roof, floor or chassis components, constituent parts of boats such as the hull or interior fitting, decorative strips in motor vehicles or aircraft, housings or components for electronic or electrotechnical devices, for example computers or telephones, bicycle components such as forks, frames, brakes, gears, ortheses, prostheses, joints, constituent parts of robots such as robot arms, handling and transport systems, receivers for bearing seats, spectacle frames, helmets or seat-securing, seat-reinforcing or seat-panelling elements in motor vehicle and aircraft construction, pressure vessels such as gas bottles, support structures for vessels, frames, oil tanks, electronic components such as antennas or battery housing, components for energy generation such as photovoltaic or wind energy plants, machine elements such as cogs or racks. Equally suitable application sectors are frames, profiles, façade elements or guide strips for windows and doors in the field of house construction and architecture.

The invention further provides for the use of a composition comprising at least one copolyamide-based hotmelt adhesive as adhesion promoter between a fibre composite material as material B and a material A for production of a hybrid component of the invention. In addition, the composition may be used for production of an extended hybrid component.

Fibre Composite Material

A fibre composite material is a multiphase or mixed material consisting of fibres and a matrix as main components. As a result of interactions between the two components, this material has higher-quality properties than either of the two components involved individually.

Suitable fibres are, for example, inorganic fibres such as basalt fibres, boron fibres, glass fibres, ceramic fibres or silica fibres, metallic fibres such as steel fibres, organic fibres such as aramid fibres, carbon fibres, polyester fibres, nylon fibres, polyethylene fibres, polymethylmethacrylate fibres, polyimide fibres or fibres made from polyaryl ether ketones, and natural fibres such as wood fibres, flax fibres, hemp fibres or subtropical and tropical fibres such as jute fibres, kenaf fibres, ramie fibres or sisal fibres. Preferred fibres are selected from glass fibres and carbon fibres.

The fibres can be divided as follows according to fibre length:

The length of short fibres is about 0.1 to 1 mm. The term long fibres is used for fibres with length about 1 to 50 mm. The term continuous fibres is used when the length is more than 50 mm. Length is defined as the number-average fibre length in the matrix after production of the fibre composite material in accordance with DIN ISO 22314.

Preferably, long or continuous fibres are used in material B. More preferably, the fibres have a length of at least 1.5 mm, more preferably at least 5 mm and most preferably at least 10 mm. These materials B are most preferred for hybrid components or extended hybrid components having metals as material A.

The dry fibres (without matrix) be be present in the form of rovings or semi-finished products (semi-finished fibre products). The semi-finished products can be produced, for example, by weaving, braiding or stitching. The semi-finished fibre products include, for example, woven fabrics, laid scrims including multiaxial laid scrims, knitted fabrics, braids, mats, nonwoven fabrics, fine-cut fabrics or spacer fabrics.

Rovings refer to a bundle, strand or multifilament yarn composed of filaments (continuous fibres) arranged in parallel. The filaments most commonly combined to form rovings are those made from glass, aramid or carbon. The cross section of a roving is usually elliptical or rectangular. However, there are also rovings with a slight protective twist (e.g. 10 twists/m), which makes the cross section rounder.

The fibre composite materials can be subdivided into fibre-plastic composites in which polymers are used as matrix, and other fibre composite materials.

The matrix of the other fibre composite materials is typically selected from metals, ceramics and carbon.

Matrices selected for the fibre-plastic composites are typically polymers such as thermosets, elastomers and thermoplastics, preference being given to thermoplastics.

The polymers may comprise reinforcers or fillers such as talc or chalk. The plastics may further comprise additives, for example stabilizers, impact modifiers, flow aids and pigments.

Particularly preferred thermoplastics are, for example, polybutylene terephthalates, polyaryl ether ketones such as polyether ether ketones, polyolefins such as polypropylene, polyphenylene sulphide, polycarbonates, polyetherimides, polyurethanes, aliphatic or semiaromatic polyamides, plastics mixtures comprising polyamides, styrene polymers such as acrylonitrile-butadiene-styrene, polyalkyl(meth)acrylates such as polymethylmethacrylate, and also mixtures of the abovementioned plastics. Mixtures of polycarbonates and acrylonitrile-butadiene-styrene are likewise suitable. Preference is given to aliphatic or semiaromatic polyamides, plastics mixtures comprising polyamides, polybutylene terephthalates, polyolefins, and also mixtures of the abovementioned polymers, particular preference being given here to polyamides.

Preferred polyamides (PA) are selected from the group consisting of nylon-6, nylon-6,6, nylon-6,10, nylon-6,12, nylon-6,13, nylon-6,14, nylon-10,6, nylon-10,10, nylon-10,12, nylon-12,12, nylon-11, nylon-12, polyphthalamides, optically transparent polyamides and mixtures based on these polyamides. Particularly preferred polyamides are selected from nylon-6, nylon-6,6, nylon-12, polyphthalamides, optically transparent polyamides and mixtures of these. Suitable polyamides are available by way of example as VESTAMID LX9012 from Evonik Industries.

Optically transparent polyamides include microcrystalline polyamides comprising linear aliphatic dicarboxylic acids and cycloaliphatic diamines, amorphous polyamides comprising linear aliphatic dicarboxylic acids and cycloaliphatic diamines and optionally lactams or aminocarboxylic acids, amorphous polyamides comprising terephthalic acid and cycloaliphatic or branched aliphatic diamines and optionally lactams or aminocarboxylic acids, or amorphous polyamides comprising isophthalic acid and cycloaliphatic or linear or branched aliphatic diamines and optionally lactams or aminocarboxylic acids. Suitable optically transparent polyamides are by way of example amides made of dodecanedioic acid and of an isomer mixture of 4,4′-bis(aminocyclohexyl)methane, of terephthalic acid and of the isomer mixture of 2,2,4- and 2,4,4-trimethylhexamethylenediamine, of dodecanedioic acid and of the isomer mixture of 3,3′-dimethyl-4,4′-bis(aminocyclohexyl)methane, of laurolactam, isophthalic acid and of the isomer mixture of 3,3′-dimethyl-4,4′-bis(aminocyclohexyl)methane or of tetradecanedioic acid and of the isomer mixture of 3,3′-dimethyl-4,4′-bis(aminocyclohexyl)methane. Polyamides of this type are described by way of example in DE-A-102007062063 or WO-A-2008025729. Optically transparent polyamides are available by way of example with trade names Trogamid (Evonik, Germany), Grilamid (EMS-Chemie, Germany), or Durethan (Lanxess, Germany).

The fibre composite materials further comprise thermoplastics with homogeneous reinforcement (polymer fibres in polymer matrix of the same composition).

The aforementioned thermoplastic matrix polymers may additionally be crosslinked. For example, the crosslinking can be effected during the production of the fibre composite material or in a subsequent step.

Suitable thermosets are, for example, epoxy resins, unsaturated polyester resins, vinyl ester resins, phenacrylate resins, phenol resins, methacrylate resins or isocyanate resins (cf. G. Ehrenstein: Faserverbund-Kunststoffe [Fibre Composite Plastics], Hanser-Verlag, 2nd edition 2006, page 53 ff., ISBN 978-3-446-22716-3).

Particularly preferred fibre composite materials are selected from carbon fibre-reinforced plastics and glass fibre-reinforced plastics.

The fibres can have orientation in the matrix or no orientation, preferably having orientation. Examples of fibre composite materials comprising oriented fibres are UD laid scrims, UD tapes (UD=unidirectional) and woven fabrics. Unoriented fibres are present by way of example in nonwovens.

The fibre-plastic composites can moreover take the form of semifinished fibre-matrix products. These may have been preimpregnated. Preimpregnated semi-finished fibre-matrix products especially include thermoplastic and thermoset semi-finished products. The preimpregnated semifinished fibre-matrix products may take the form of sheets, of strips or of strands.

Among the semifinished thermoplastic products are by way of example glass-mat-reinforced thermoplastics (GMT), or long-fibre-reinforced thermoplastics (LFT) and thermoplastic preimpregnated fibres (prepregs). Thermoplastic prepregs in the form of sheets are also called organopanels (cf. Tagungsband zur Fachtagung “Thermoplastische Faserverbundkunststoffe” [Proceedings of the Conference on “Thermoplastic fibre composite materials”], 15.-16.05.2013 in Fürth, Carl Hanser Verlag Munich 2013, ISBN 978-3-446-43864-4, pp. 5, 13 and 17).

Thermoset semi-finished products are, for example, sheet moulding compounds (SMCs), bulk moulding compounds (BMCs) and thermoset preimpregnated fibres (prepregs).

Before the application of material A, the fibre composite material may be trimmed, formed or shaped. The forming process may precede or follow the application of the adhesion promoter composition.

The person skilled in the art is aware of the production of fibre composite materials made of the fibres described above and of the matrix.

Metals

Examples of suitable metals are iron-containing alloys such as steel, aluminium, copper, magnesium, titanium, and also alloys of the abovementioned metals. Preferred metals are steel, titanium, aluminium, and also alloys of the abovementioned metals, particular preference being given to steel and aluminium, and aluminium alloys. The metals may also take the form of foam or can be present in a honeycomb structure.

Preferred steels are unalloyed steels and stainless steels. Steels with a protective coating are particularly preferred. Suitable coatings are by way of example coatings made of zinc, aluminium-silicon, aluminium-zinc, zinc-aluminium, zinc-iron or zinc-magnesium, preference being given here to aluminium-silicon, zinc-aluminium and zinc. The composition of the coatings is defined by way of example in the brochure “Schmelztauchveredeltes Band and Blech” [Hot-dip-coated Strip and Sheet] from the Steel Information Centre in the Stahl-Zentrum, Düsseldorf, Germany, 2010 Edition.

Before the application of the fibre composite material (material B), the metal may be trimmed, formed or shaped. The forming process can take place before or after the application of the adhesion promoter composition.

Before application of the adhesion promoter compositions, it is possible to apply a conversion coat to all or some of the surface of the metal, in order to pretreat the surface. The metal may be cleaned before the pretreatment, or can already have metallic protective coatings. The metal cleaning process is known to the person skilled in the art.

The pretreatment may use converting agents. The converting agents are usually used in the form of aqueous solutions. Converting agents that can be used are commercially available passivating agents and products for conversion treatment, for example zinc phosphating agents, iron phosphating agents, and also phosphoric acid solutions comprising titanates or zirconates. From a technical point of view it is likewise possible to use chromating agents, but these are less preferred because they are hazardous to health.

It is moreover possible to obtain the conversion coat by flame pyrolysis deposition of amorphous silicate on the surface of the metal. The surface to be treated is passed through the oxidizing region of a gas flame into which a silicon-containing substance, the precursor, has been dosed. This is consumed by combustion, and the residue deposits in the form of amorphous silicate as firmly adhering layer in layer thicknesses of about 20 to 40 nm on the surface.

Treatment of a surface is achieved by using an operating gas to produce a plasma jet or a combustion gas to produce a flame jet, this being used to coat the surface, where at least one precursor material is introduced into the operating gas and/or into the plasma jet or into the combustion gas and/or into the flame jet, and is reacted in the plasma jet or flame jet, where at least one reaction product of at least one of the precursors is deposited on the surface and/or on at least one layer arranged on the surface. A process of this type is described by way of example in DE-A-102009042103.

Plastic

The plastic can be applied to material B in a known manner, for example by injection moulding, pressing, laminating, insert moulding or (co-)extrusion, in which case the material should already have been coated with the composition. Injection moulding technology is preferably used to inject the plastic. Material B may have been subjected to preconditioning in the range from 50° C. to 250° C. in order to raise the temperature in the region of contact with the plastic, for example in the case of in-mould coating or in the case of co-extrusion, for good bonding between the adhesion promoter and the plastic.

Alternatively, the plastic may already be present, optionally having been coated with the composition, and may then be bonded to material B.

Suitable plastics comprise by way of example polybutylene terephthalates, polyolefins, polyetherimides, polycarbonates, polyurethanes, aliphatic or semiaromatic polyamides, plastics mixtures comprising polyamides, styrene polymers such as acrylonitrile-butadiene-styrene, polyalkyl(meth)acrylates such as polymethylmethacrylate, polymethacrylimide (for example Rohacell from Evonik, Germany), and also mixtures of the abovementioned plastics. Mixtures of polycarbonates, acrylonitrile-butadiene-styrene or polyether-block-amides are likewise suitable. Preference is given to aliphatic or semiaromatic polyamides, plastics mixtures comprising polyamides, polybutylene terephthalates, polyolefins, and also mixtures of the abovementioned plastics, particular preference being given here to polyamides. The plastics can comprise reinforcement (reinforcing materials), preference being given here to glass fibre-reinforced (GF) or carbon fibre-reinforced (CF) plastics. The plastics can moreover comprise fillers such as talc powder or chalk. The plastics may further comprise additives, for example stabilizers, impact modifiers, flow aids and pigments. The reinforcers are preferably distributed randomly in their matrix. In addition, the reinforcers preferably have a length of less than 5 mm, preferably less than 1 mm.

Preferred polyamides are selected from the group consisting of nylon-6, nylon-6,6, nylon-6,10, nylon-6,12, nylon-6,13, nylon-6,14, nylon-10,6, nylon-10,10, nylon-10,12, nylon-12,12, nylon-11, nylon-12, polyphthalamides and mixtures based on these polyamides. Particularly preferred polyamides are selected from nylon-6, nylon-6,6, nylon-6,10, nylon-10,10, and mixtures of these. Suitable polyamides are available by way of example as VESTAMID LX9012 or LGF30 from Evonik Industries.

Adhesion Promoter Composition

The adhesion promoter composition comprises at least one copolyamide-based hotmelt adhesive. The adhesion promoter composition can be present in solution or in dispersion, or in the form of solid.

The hotmelt adhesive comprises at least one copolyamide. The copolyamide can be produced from amide monomers and from comonomers. The comonomers are preferably used to obtain copolyamides with a melting point from 95° C. to 175° C.

The amide monomers are preferably selected from the group consisting of laurolactam, aminoundecanoic acid and mixtures thereof. Particular preference is given to copolyamides based on laurolactam.

The comonomers are preferably selected from aliphatic or cycloaliphatic diamines, aliphatic or cycloaliphatic dicarboxylic acids, lactams and mixtures thereof. The comonomers preferably comprise, mutually independently, from 4 to 18 carbon atoms. Suitable dicarboxylic acids are by way of example adipic acid, sebacic acid and dodecanedioic acid. Suitable diamines are by way of example hexamethylenediamine, decamethylenediamine and dodecamethylenediamine. Lactams such as caprolactam can likewise be used as comonomer.

Preferred comonomers are caprolactam and a polymer made with adipic acid and hexamethylenediamine, preferably in a ratio by mass of 1:1.

An excess of amine groups in the diamines gives copolyamides having reactive amino end groups.

The amine numbers of the copolyamides are preferably from 75 to 400 mmol/kg.

The weight-average molar mass of the copolyamides is preferably in the range from 15 000 to 70 000 g/mol (measured by means of gel permeation chromatography (GPC) against a polystyrene standard). The relative solution viscosity is preferably from 1.2 to 1.8 (determined in accordance with ISO 307).

The copolyamides and the hotmelt adhesive can be used in the compositions in solution, in dispersion or in powder form, preference being given here to the powder form. A suitable solvent is by way of example m-cresol.

The powder form can by way of example be obtained by milling, the grain diameter here with preference being <200 μm, more preferably <100 μm and with particular preference <70 μm (sieve analysis).

In one preferred embodiment of the invention, at least one epoxy component and at least one blocked polyisocyanate have been added to the copolyamide, as other constituents of the hotmelt adhesive.

The epoxy index of the epoxy component is typically from 1 to 2 eq/kg. The epoxy equivalent weight of the epoxy resins used can be from 400 to 4000 g/mol, preferably from 700 to 3000 g/mol and with preference from 875 to 1000 g/mol (determined in accordance with SMS 2026).

The content of OH groups in suitable epoxy resins is preferably from 2000 to 4500 mmol/kg, with preference from 2300 to 4000 mmol/kg (method of SMS 2367). Compounds based on diols or on polyols or dicarboxylic acids can by way of example be used as epoxy component, preference being given here to diols and particular preference being given here to corresponding phenol-diol derivatives. Very particularly preferred phenol-diol derivatives are bisphenols, in particular bisphenol A. The epoxy component is usually obtained by reaction with epichlorohydrin.

The density of suitable epoxy resins is from 1 to 1.3 kg/L, preferably from 1.15 to 1.25 kg/L (25° C.; determined in accordance with ASTM D792). The glass transition temperature (Tg) can be from 20° C. to 100° C., preferably from 25° C. to 90° C., with preference from 40° C. to 60° C. and with particular preference from 45 to 55° C. (determined in accordance with ASTM D3418). The melting range is usually in the range from 45° C. to 150° C. (in accordance with DIN 53181). Suitable epoxy resins are obtainable by way of example as EPIKOTE resin, for example EPIKOTE Resin 1001 or 1009 from Hexion Specialty Chemicals, Inc.

The hotmelt adhesive preferably comprises a proportion of from 2.5 to 10% by weight of the epoxy component, more preferably from 4 to 6% by weight, based in each case on the total weight of the hotmelt adhesive.

The hotmelt adhesive may further comprise hardeners such as dicyandiamide (DCD), preferably in proportions of from 3 to 6% by weight, based on the total weight of the epoxy resin. To accelerate curing, urea derivatives such as monuron or fenuron can be added, and it is thus possible to lower the curing temperatures and/or shorten the curing times.

The proportion of blocked polyisocyanate is preferably from 2.5 to 15% by weight, more preferably from 4 to 6% by weight, based in each case on the total weight of the hotmelt adhesive.

The blocked polyisocyanate component can be aromatic, aliphatic or cycloaliphatic, preference being given here to aliphatic or cycloaliphatic polyisocyanates. Blocking agents for isocyanates such as oximes, phenols or caprolactam are known to the person skilled in the art. It is preferable that, for blocking purposes, the polyisocyanate component takes the form of uretdione. Typical examples are marketed as VESTAGON by Evonik Industries, Germany.

The adhesion promoter composition can comprise self-crosslinking or externally crosslinking binders (in relation to the term “Bindemittel” [Binders] cf. Römpp Lexikon Lacke und Druckfarben [Römpp's Encyclopaedia of Coating Materials and Printing Inks], Georg Thieme Verlag, Stuttgart, N.Y., 1998, Bindemittel, pp. 73 and 74). For the purposes of the present invention, the term “self-crosslinking” denotes the property of a binder of entering into crosslinking reactions with itself. A precondition for this is that complementary reactive functional groups are present in the binders and react with one another and thus lead to crosslinking. Or else the binders comprise reactive functional groups which react “with themselves”. Binder systems described as externally crosslinking are in contrast those in which one type of the complementary reactive functional groups is present in the binder and the other type is present in a hardener or crosslinking agent. For additional information here, reference is made to Römpp Lexikon Lacke und Druckfarben, Georg Thieme Verlag, Stuttgart, N.Y., 1998, Härtung [Curing], pp. 274 to 276, in particular lower part of p. 275.

The adhesion promoter composition can moreover comprise electrically conductive substances selected from graphite, carbon black, zinc dust and mixtures of these substances, thus giving electrically conductive adhesion promoter compositions.

The metal-plastic composite comprising coatings of electrically conductive adhesion promoter compositions may be provided with a cathodic electrocoat (CEC).

The adhesion promoter compositions can moreover comprise colorants, preferably pigments. Functional pigments such as corrosion-protection pigments can moreover be present.

The adhesion promoter composition may further comprise functionalized polyolefins in order to improve adhesion to polyolefins. Compositions of this kind are described by way of example in WO 2010/136241.

Suitable hotmelt adhesives are available by way of example as VESTAMELT from Evonik Industries AG, Germany. Examples include X1027-P1, X1038-P1, X1316 P1 and X1333-P1.

Other materials that can be present alongside the hotmelt adhesive are graft copolymers made of polyamine and of polyamide-forming monomers such as lactams and/or ω-aminocarboxylic acids, as described in EP1065236A2:

The concentration of amino groups in the graft copolymer is preferably in the range from 100 to 2500 mmol/kg.

Examples of substance classes that can be used as polyamine are the following:

-   -   polyvinylamines (Römpp Chemie Lexikon, [Rompp's Chemical         Encyclopaedia] 9th Edn. Vol. 6, p. 4921, Georg Thieme Verlag         Stuttgart 1992);     -   polyamines that are produced from alternating polyketones (DE-A         196 54 058);     -   dendrimers, for example     -   ((H₂N—(CH₂)₃)₂N—(CH₂)₃)₂—N(CH₂)₂—N((CH₂)₂—N((CH₂)₃—NH₂)₂)₂         (DE-A-196 54 179) or     -   tris(2-aminoethyl)amine,         N,N-bis(2-aminoethyl)-N′,N′-bis[2-[bis(2-aminoethyl)amino]ethyl]-1,2-ethanediamine,     -   3,15-bis(2-aminoethyl)-6,12-bis[2-[bis(2-aminoethyl)amino]ethyl]-9-[2-[bis[2-bis(2-aminoethyl)amino]ethyl]amino]ethyl]-3,6,9,12,15-pentaazaheptadecane-1,17-diamine         (J. M. Warakomski, Chem. Mat. 1992, 4, 1000-1004);     -   linear polyethyleneimines which can be produced by         polymerization of 4,5-dihydro-1,3-oxazoles followed by         hydrolysis (Houben-Weyl, Methoden der Organischen Chemie         [Methods for Organic Chemistry]), vol. E20, pp. 1482-1487, Georg         Thieme Verlag Stuttgart, 1987);     -   branched polyethyleneimines which are obtainable by         polymerization of aziridines (Houben-Weyl, Methoden der         Organischen Chemie), vol. E20, pp. 1482-1487, Georg Thieme         Verlag Stuttgart, 1987) and which generally have the following         amino group distribution:     -   from 25 to 46% of primary amino groups,     -   from 30 to 45% of secondary amino groups and     -   from 16 to 40% of tertiary amino groups.

In the preferred case the number-average molar mass M_(n) of the polyamine is at most 20 000 g/mol, particularly at most 10 000 g/mol and in particular at most 5000 g/mol.

Lactams and ω-aminocarboxylic acids which can be used as polyamide-forming monomers comprise from 4 to 19 carbon atoms, in particular from 6 to 12. It is particularly preferable to use ε-caprolactam and laurolactam or the relevant ω-aminocarboxylic acids. The molar ratio of C12 to C6 unit is preferably from 4:1 to 1:4. The ratio by mass of hotmelt adhesive to graft copolymer is preferably from 19:1 to 1:1.

In the simplest case, the functionalized polyolefin is polypropylene-based. However, ethylene/C₃-C₁₂-α-olefin copolymers are also suitable. An example of a C₃-C₁₂-α-olefin used is propene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene or 1-dodecene. The ethylene/C₃-C₁₂-α-olefin copolymers can moreover also comprise up to at most 10% by weight of olefin dienes such as ethylidenenorbornene or 1,4-hexadiene. Functionalization is preferably provided by acid anhydride groups, these being introduced in a known manner through thermal or free-radical reactions of the main-chain polymer with an unsaturated dicarboxylic anhydride or with an unsaturated dicarboxylic acid. Examples of suitable reagents are maleic anhydride and itaconic anhydride. The quantity grafted onto the material in this method is from 0.1 to 4% by weight, based on the total weight of the functionalized polyolefins, and another monomer such as styrene can also be used here.

Maleic-acid-grafted polyolefins are widely used for industrial applications, in particular for impact modifications or as compatibilizers in blends and mechanically reinforced systems (Polymer, 2001, 42, 3649-3655 and literature cited). The source mentioned also describes by way of example the production of functionalized polyolefins of this type.

A typical functionalized polyolefin is the polypropylene-based, acid anhydride-grafted material Admer QB 520 E (Mitsui Chemicals). It is also possible in principle to use maleic-acid-grafted polypropylenes from Kometra (e.g. SCONA TPPP 8012), these being more free-flowing.

Another possible functionalization method consists in the mixing, in the melt, of unfunctionalized polyolefins with reactive compatibilizers which comprise epoxy or carboxylic anhydride groups. Typical examples are copolymers composed of ethylene and of one or more unreactive acrylic monomers with maleic anhydride or glycidyl methacrylate. Lotader AX8900 (Arkema) is a typical representative material having glycidyl methacrylate units.

The ratio of polyamide component to polyolefin component is from 9:1 to 2:3.

The present invention is explained in more detail below with reference to examples. Alternative embodiments of the present invention are obtainable analogously.

EXAMPLES A) Hybrid Component Composed of Fibre Composite Material and Metal

1. Structure: Metal—Adhesion Promoter Coating—Fibre Composite Material—Plastic (Extended Hybrid Component)

Unpretreated metal sheets (sheet thickness 1.5 mm) of ZSTE 800 steel to DIN EN 10142 were phosphated with converting agent. Granodine 958 A from Henkel, Germany was used as converting agent, comprising inter alia phosphoric acid and zinc bis(dihydrogenphosphate), and Deoxylyte 54NC was used for post-passivation.

The conversion solution was applied in accordance with manufacturer's instructions by means of immersion into the solutions and drying of the layers, and then the metal samples were coated with an adhesion promoter composition. The composition applied comprised

-   -   H1: Solvent-containing spray coating comprising about 30% by         weight of a copolyamide-based hotmelt adhesive comprising an         epoxy component and a blocked polyisocyanate and     -   H2: Copolyamide-based hotmelt adhesive (Vestamelt X1333-P1 from         Evonik) comprising an epoxy component and a blocked         polyisocyanate in the form of powder coating.

The two compositions H1 and H2 comprise the same copolyamide.

The coating system was applied by the spray process with a layer thickness of from 50 to 70 μm, and the powder coating was applied electrostatically with a layer thickness of from 50 to 100 μm. The spray coating was stoved for 5 min at 175° C., and the powder coating was stoved for 5 min at 200° C. For this purpose, the coated metal sheets were placed in a preheated autoclave (oven).

After the stoving procedure, guillotine shears were used to cut the metal sheets into strips fitting the injection moulding cavity with dimensions of 20.0 mm×50.0 mm (tolerance+0−0.2 mm).

Fibre composite material inserts used were continuous carbon fibre-reinforced UD tapes having a matrix of nylon-12. The UD tapes have a matrix of nylon-12. The UD tapes were likewise cut to size with guillotine shears to dimensions fitting the injection moulding cavity of about 20.0 mm×50.0 mm.

For production of the final hybrid components with and without fibre composite inserts, the strips were then placed in a temperature-controlled injection mould and in-mould-coated with a thermoplastic. The fibre composite material insert was placed onto the strip without fastening. The plastic component used was a nylon-12 GF30 (VESTAMID L-GF30 from Evonik Industries AG, Germany).

The plastic was processed in an Arburg V370 at a melt temperature of 280° C., a mould temperature of 120° C., and an injection rate of about 30 ccm/s. It was important here to provide an injection delay of about 30 s, so that the metal sheet strip and composite insert inserted could be preheated to mould temperature, giving a favourable effect on adhesion. The region of overlap between plastic and metal was about 20 mm×20 mm. The sample had a total length of about 100 mm. The thickness of the insert-moulded plastic was about 6 mm, and in the overlap region about 4 mm. After demoulding, the individual tensile shear test samples were separated from the sprue.

The test samples thus produced were stored at 50% relative humidity for at least 24 h at 23° C. in order to ensure a uniform state of conditioning. The test samples are then clamped into a standard Zwick/Roell Z-020 tensile tester and tested with a velocity of 5 mm/min at 23° C. with a distance between the clamps and the overlap region of about 15 mm/side.

Fibre composite Adhesion Example material promoter Adhesion in MPa 1 without without 0 2 without H1 8.8 3 with without 0  4* with H1 8.5 5 without without 0 6 without H2 10.6 7 with without 0  8* with H2 9.3 *inventive

The results show that it is possible through an adhesion promoter coating of the metal component to achieve increased bond strength between UD tape and metal in hybrid components compared to systems without adhesion promoter. It is additionally demonstrated that the use of the fibre composite material does not result in any significant decrease in adhesion.

2. Structure: Metal—Adhesion Promoter Coating—Fibre Composite Material

Converting agents were used to phosphate or chromate metal sheets (sheet thickness 1.0 mm) which have not been pretreated. Granodine 958 A from Henkel, Germany, for galvanized steel sheets DX56D Z140 to DIN EN 10346 (M1) was used as converting agent, comprising inter alia phosphoric acid and zinc bis(dihydrogenphosphate), and Deoxylyte 54NC was used for post-passivation. For aluminium sheets AlMg3 EN AW-5754 H111 to DIN EN 573-3 (M2), a conversion layer (chromation) of Alodine 1225 from Henkel, Germany, was used.

The conversion solution was applied in accordance with manufacturer's instructions by means of immersion into the solutions and drying of the layers, and then the metal samples were coated with an adhesion promoter composition. The composition applied comprised:

-   -   H1: Copolyamide-based hotmelt adhesive (Vestamelt X1333-P1 from         Evonik) comprising an epoxy component and a blocked         polyisocyanate in the form of powder coating and     -   H2: Solvent-containing spray coating comprising about 30% by         weight of a copolyamide-based hotmelt adhesive comprising an         epoxy component and a blocked polyisocyanate.

The two compositions H1 and H2 comprise the same copolyamide.

The coating system was applied by the spray process with a layer thickness of from 50 to 70 μm, and the powder coating was applied electrostatically with a layer thickness of from 50 to 100 μm. The spray coating was stoved for 5 min at 175° C., and the powder coating was stoved for 5 min at 200° C. For this purpose, the coated metal sheets were placed in a preheated autoclave (oven).

After the stoving procedure, guillotine shears were used to cut the metal sheets into strips appropriate for the pressing operation with dimensions of about 60.0 mm×25.0 mm (tolerance+0−0.2 mm).

Continuous fibre-reinforced fibre composite materials were used as composite partner. The fibre composite materials were likewise cut to size with guillotine shears to dimensions appropriate for the pressing operation of about 60.0 mm×25.0 mm. The following fibre composite materials were used:

-   -   C1: Fibre composite material composed of VESTAMID L1600         (nylon-12) and carbon fibre fabric having continuous fibres. The         fabric has a weight of about 285 g/m² with an orientation of         0°/90°. The fibre composite material sheets were produced in a         pressing process.     -   C2: Fibre composite material dynalite 102-FG290 (4)/45% type C         (PA6) and glass fibre fabric having continuous fibres from         Bond-Laminates GmbH, Germany. The fibre composite material has a         fibre volume content of about 45% by volume with an orientation         of 0°/90°.     -   C3: Fibre composite material composed of epoxy resin (Evonik         product in development) and carbon fibre fabric having         continuous fibres. The fabric has a weight of about 250 g/m²         with an orientation of 0°/90°. The fibre composite material         sheets were produced in a pressing process.     -   C4: Fibre composite material composed of polyurethane resin         (Evonik product in development) and carbon fibre fabric having         continuous fibres. The fabric has a weight of about 200 g/m²         with an orientation of 0°/90°. The fibre composite material         sheets were produced in a pressing process.

The bond between coated metal and fibre composite material was obtained by a pressing operation in a hydraulic hot press (manufacturer: Paul Weber, name: TEMPRESS). This is done by inserting the coated metal sheet having dimensions of about 60×25×1 mm into a template in one half of the hot press. A sheet of a fibre composite material having dimensions of 60×25×1 mm is positioned thereon. The half of the press on the metal sheet side is heated to about 220° C. Thereafter, the fibre composite material and the coated metal sheet are pressed at a pressure of about 32 bar with a hold time of about 5 min to give a composite body. The region of overlap between plastic and metal was about 25 mm×25 mm. The sample had a total length of about 130 mm.

The test samples thus produced were stored at 50% relative humidity for at least 24 h at 23° C. in order to ensure a uniform state of conditioning. The test samples are then clamped into a standard Zwick/Roell Z-020 tensile tester and tested with a velocity of 5 mm/min at 23° C. with a distance between the clamps and the overlap region of about 15 mm/side.

Adhesion Fibre composite Adhesion Example Metal promoter material in MPa  9 M1 without C1 2.8 10* M1 H1 C1 8.7 11* M1 H2 C1 8.9 12 M2 without C1 3.6 13* M2 H1 C1 7.8 14* M2 H2 C1 7.8 15 M1 without C2 n.m. 16* M1 H1 C2 7.6 17* M1 H2 C2 8.5 18 M2 without C2 n.m. 19* M2 H1 C2 7.5 20* M2 H2 C2 8.0 21 M1 without C3 n.m. 22* M1 H1 C3 9.1 23 M2 without C3 n.m. 24* M2 H1 C3 8.6 25 M1 without C4 n.m. 26* M1 H1 C4 8.0 27 M2 without C4 n.m. 28* M2 H1 C4 6.0 *inventive; n.m. = not measurable (no adhesion)

B) Hybrid Component Composed of Fibre Composite Material and Plastic Structure: Fibre Composite Material—Adhesion Promoter—Plastic

For production of a composite body composed of a fibre composite material and plastic by means of an adhesion promoter composition, various fibre composite material sheets of thickness 1.0 mm were used:

-   -   C1: Fibre composite material composed of VESTAMID L1600         (nylon-12) and carbon fibre fabric having continuous fibres. The         fabric has a weight of about 285 g/m² with an orientation of         0°/90°. The fibre composite material sheets were produced in a         pressing process.     -   C2: Fibre composite material composed of TROGAMID CX7323         (PACM 12) and glass fibre fabric having continuous fibres. The         fabric has a weight of about 285 g/m² with an orientation of         0°/90°. The fibre composite material sheets were produced in a         pressing process.     -   C3: Fibre composite material composed of epoxy resin (Evonik         product in development) and carbon fibre fabric having         continuous fibres. The fabric has a weight of about 250 g/m²         with an orientation of 0°/90°. The fibre composite material         sheets were produced in a pressing process.     -   C4: dynalite fibre composite material (polybutylene         terephthalate PBT) and carbon fibre fabric having continuous         fibres from Bond-Laminates GmbH, Germany. The fibre composite         material has a fibre volume content of about 45% by volume with         an orientation of 0°/90°.

The sheets were each coated with an adhesion promoter composition. The composition applied comprised

-   -   H1: Copolyamide-based hotmelt adhesive (Vestamelt X1333-P1 from         Evonik) comprising an epoxy component and a blocked         polyisocyanate in the form of powder coating and     -   H2: Copolyamide-based hotmelt adhesive (Vestamelt Z2366-P1 from         Evonik) comprising an epoxy component and a blocked         polyisocyanate, and also a functionalized polyolefin, as powder         coating.

The two compositions H1 and H2 comprise the same copolyamide.

The powder coating was applied electrostatically with a layer thickness of 50-70 μm and stoved at 160° C. for 5 min. For this purpose, the coated metal sheets were placed in a preheated autoclave (oven).

After the stoving procedure, guillotine shears were used to cut the fibre composite material sheets into strips fitting the injection moulding cavity with dimensions of 24.9 mm×59.8 mm (tolerance±0.2 mm).

For production of the final hybrid components, the fibre composite material sheets were then placed in a temperature-controlled injection mould and in-mould-coated with a thermoplastic. The following moulding compositions were used as plastics component:

-   -   K1: Nylon-6 GF30 (Durethan BKV30 H2.0 from Lanxess, Germany)     -   K2: Long glass fibre-reinforced polypropylene LGF30 (CELSTRAN         PP-GF30-05CNO1 from TICONA)     -   K3: PACM 12 (TROGAMID CX7323 from Evonik Industries AG)     -   K4: PA1010 GF65 (thermally stabilized polyamide reinforced with         65% glass fibres from Evonik Industries AG)

The plastics were processed in an Arburg Allrounder 420 C injection moulding machine at a melt temperature of 280° C., a mould temperature of 80° C. or 120° C., and an injection rate of about 30 ccm/s. For the polypropylene LGF30, a melt temperature of 270° C., a mould temperature of 70° C. and then injection rate of about 30 ccm/s were used. It was important here to provide an injection delay of about 15-30 s, so that the fibre composite material sheet inserted could be preheated to mould temperature, giving a favourable effect on adhesion. The region of overlap between plastic and fibre composite material sheet was about 25 mm×25 mm. The sample had a total length of about 130 mm. The thickness of the overmoulded plastic was about 4 mm. After demoulding, the individual tensile shear test samples were separated from the sprue.

The test samples thus produced were stored at 50% relative humidity for at least 24 h at 23° C. in order to ensure a uniform state of conditioning. The test samples are then clamped into a standard Zwick/Roell Z-020 tensile tester and tested with a velocity of 5 mm/min at 23° C. with a distance between the clamps and the overlap region of about 25 mm/side.

Fibre Mould composite Adhesion temperature Adhesion in Example Plastic material promoter in ° C. MPa 29 K1 C1 without 80 2.6 30 K1 C1 without 120 3.6 31* K1 C1 H1 80 9.3 32* K1 C1 H1 120 12.4  33 K2 C1 without 70 0.6 34* K2 C1 H2 70 5.2 35 K3 C2 without 80 n.r. 36* K3 C2 H1 80 2.3 37 K4 C3 without 80 material fracture 38* K4 C3 H1 80 material fracture 39 K4 C4 without 80 n.m. 40* K4 C4 H1 80 5.8 *inventive; n.r.: no result; n.m.: not measurable: (no adhesion)

The results show that the adhesion promoter variants can achieve increased bond strength between fibre composite material sheets and unlike plastic in hybrid components compared to systems without adhesion promoter.

C) Hybrid Component Composed of Fibre Composite Material and Metal Structure: Fibre Composite Material—Adhesion Promoter—Metal

To obtain a composite composed of fibre composite material and metal, various fibre composite material sheets of thickness 1.0 mm were used:

-   -   C1: Fibre composite material composed of VESTAMID L1600         (nylon-12) and carbon fibre fabric having continuous fibres. The         fabric has a weight of about 285 g/m² with an orientation of         0°/90°. The fibre composite material sheets were produced in a         pressing process.     -   C2: Fibre composite material dynalite 102-FG290 (4)/45% type C         (PA6) and glass fibre fabric having continuous fibres from         Bond-Laminates GmbH, Germany. The fibre composite material has a         fibre volume content of about 45% by volume with an orientation         of 0°/90°.

C3: Fibre composite material composed of TROGAMID CX7323 (PACM 12) and carbon fibre fabric having continuous fibres. The fabric has a weight of about 250 g/m² with an orientation of 0°/90°. The fibre composite material sheets were produced in a pressing process.

-   -   C4: Fibre composite material composed of epoxy resin (Evonik         product in development) and carbon fibre fabric having         continuous fibres. The fabric has a weight of about 250 g/m²         with an orientation of 0°/90°. The fibre composite material         sheets were produced in a pressing process.     -   C5: Fibre composite material composed of VESTAMID HTplus M1000         (PA6T) and carbon fibre fabric having continuous fibres. The         fabric has a weight of about 285 g/m² with an orientation of         0°/90°. The fibre composite material sheets were produced in a         pressing process.

The sheets were each coated with an adhesion promoter composition. The composition applied comprised

-   -   H1: Copolyamide-based hotmelt adhesive (Vestamelt X1333-P1 from         Evonik) comprising an epoxy component and a blocked         polyisocyanate in the form of powder coating and     -   H2: Solvent-containing spray coating comprising about 30% by         weight of a copolyamide-based hotmelt adhesive comprising an         epoxy component and a blocked polyisocyanate.

The two compositions H1 and H2 comprise the same copolyamide.

The powder coating was applied electrostatically with a layer thickness of 70-100 μm and stoved at 160° C. for 5 min. The spray coating was applied electrostatically with a layer thickness of 50-70 μm and stoved at 160° C. for 5 min. For this purpose, the coated fibre composite materials were placed in a preheated autoclave (oven).

After the stoving procedure, guillotine shears were used to cut the sheets of fibre composite materials into strips appropriate for the pressing operation with dimensions of 60.0 mm×25.0 mm (tolerance+0−0.2 mm).

Metal sheets were used as composite partners and were phosphated or chromated with converting agents. Granodine 958 A from Henkel, Germany, for galvanized steel sheets DX56D Z140 to DIN EN 10346 (M1) was used as converting agent, comprising inter alia phosphoric acid and zinc bis(dihydrogenphosphate), and Deoxylyte 54NC was used for post-passivation. For aluminium sheets AlMg3 EN AW-5754 H111 to DIN EN 573-3 (M2), a conversion layer (chromation) of Alodine 1225 from Henkel, Germany, was used. The metal sheets were likewise cut to size with guillotine shears to dimensions appropriate for the pressing operation of about 60.0 mm×25.0 mm.

The bond between coated fibre composite material and metal was obtained by a pressing operation in a hydraulic hot press (manufacturer: Paul Weber, name: TEMPRESS). This is done by inserting the uncoated metal sheet having dimensions of about 60×25×1 mm into a template in one half of the hot press. A sheet of a fibre composite material having dimensions of 60×25×1 mm is positioned thereon. The press is heated on the metal sheet side to about 230° C. Thereafter, the fibre composite material and the coated metal sheet are pressed at a pressure of about 32 bar with a hold time of about 5 min to give a composite body. The region of overlap between plastic and metal was about 25 mm×25 mm. The sample had a total length of about 130 mm.

The test samples thus produced were stored at 50% relative humidity for at least 24 h at 23° C. in order to ensure a uniform state of conditioning. The test samples are then clamped into a standard Zwick/Roell Z-020 tensile tester and tested with a velocity of 5 mm/min at 23° C. with a distance between the clamps and the overlap region of about 15 mm/side.

Fibre composite Adhesion Adhesion in Example material promoter Metal MPa 41 C1 without M1 n.m. 42* C1 H1 M1 6.7 43* C1 H2 M1 7.2 44 C1 without M2 1.8 45* C1 H1 M2 7.3 46* C1 H2 M2 7.5 47 C2 without M1 0.6 48* C2 H1 M1 7.9 49* C2 H2 M1 8.1 50 C2 without M2 n.m. 51* C2 H1 M2 7.1 52* C2 H2 M2 6.4 53 C3 without M1 n.m. 54* C3 H1 M1 7.4 55 C3 without M2 n.m. 56* C3 H1 M2 7.9 57 C4 without M1 1.5 58* C4 H1 M1 7.1 59 C4 without M2 n.m. 60* C4 H1 M2 8.0 61 C5 without M1 0.7 62* C5 H1 M1 6.8 63 C5 without M2 n.m. 64* C5 H1 M2 7.5 *inventive; n.m. = not measurable (no adhesion)

D) Hybrid Component Composed of Plastic and Fibre Composite Material Structure: Plastic—Adhesion Promoter—Fibre Composite Material

To obtain a composite composed of coated plastic and a fibre composite material, various injection-moulded plastic sheets having dimensions of about 60×25 mm and a thickness of about 4.0 mm were used:

K1: Nylon-6 GF30 (Durethan BKV30 H2.0 from Lanxess, Germany) K2: Polyphthalamide PA6T CF30 (VESTAMID HTPIus TGP3561 from Evonik Industries AG)

A powder coating H1 composed of a copolyamide-based hotmelt adhesive (Vestamelt X1333-P1 from Evonik) comprising an epoxy component and a blocked polyisocyanate was applied to the plastics sheets.

The powder coating was applied electrostatically with a layer thickness of 50-70 μm and stoved at 160° C. for 5 min. For this purpose, the coated metal sheets were placed in a preheated autoclave (oven).

Composite partners used were sheets of about 60×25×1 mm of a fibre composite material. The fibre composite material consists of VESTAMID L1600 (nylon-12) and carbon fibre fabric having continuous fibres. The fabric has a weight of about 285 g/m² with an orientation of 0°/90°. The fibre composite material sheets were produced in a pressing process.

Guillotine shears were used to cut the fibre composite material sheets into a shape fitting the injection moulding cavity with dimensions of 24.9 mm×59.8 mm (tolerance±0.2 mm).

The bond between coated plastic and fibre composite material was obtained by a pressing operation in a hydraulic hot press (manufacturer: Paul Weber, name: TEMPRESS). This is done by inserting the coated plastic into a template in one half of the hot press. A sheet of a fibre composite material is positioned thereon. Before the joining operation, the press is heated to about 200° C. Thereafter, the fibre composite material and the coated plastic are pressed at a pressure of about 32 bar with a hold time of about 5 min to give a composite body. The region of overlap between plastic and metal was about 25 mm×25 mm. The test sample had a total length of about 130 mm.

The test samples thus produced were stored at 50% relative humidity for at least 24 h at 23° C. in order to ensure a uniform state of conditioning. The test samples are then clamped into a standard Zwick/Roell Z-020 tensile tester and tested with a velocity of 5 mm/min at 23° C. with a distance between the clamps and the overlap region of about 15 mm/side.

Adhesion Adhesion in Example Plastic promoter MPa 65 K1 without 0.8 66* K1 H1 6.5 67 K2 without n.m. 68* K2 H1 8.0 *inventive; n.m. = not measurable (no adhesion)

E) Hybrid Component Composed of Fibre Composite Material and Fibre Composite Material Structure: Fibre Composite Material—Adhesion Promoter—Fibre Composite Material

To obtain a composite composed of a coated fibre composite material and an uncoated fibre composite material, suitable pressing tests were conducted in a hot press. The following fibre composite materials of thickness about 1.5 mm were used:

-   -   C1: Fibre composite material composed of VESTAMID L1600         (nylon-12) and carbon fibre fabric having continuous fibres. The         fabric has a weight of about 285 g/m² with an orientation of         0°/90°. The fibre composite material sheets were produced in a         pressing process.     -   C2: Fibre composite material dynalite 102-FG290 (4)/45% type C         (PA6) and glass fibre fabric having continuous fibres from         Bond-Laminates GmbH, Germany. The fibre composite material has a         fibre volume content of about 45% by volume with an orientation         of 0°/90°.     -   C3: Fibre composite material composed of TROGAMID CX7323         (PACM 12) and carbon fibre fabric having continuous fibres. The         fabric has a weight of about 250 g/m² with an orientation of         0°/90°. The fibre composite material sheets were produced in a         pressing process.     -   C4: Fibre composite material composed of polyurethane resin         (Evonik product in development) and carbon fibre fabric having         continuous fibres. The fabric has a weight of about 200 g/m²         with an orientation of 0°/90°. The fibre composite material         sheets were produced in a pressing process.

C5: Fibre composite material composed of epoxy resin (Evonik product in development) and carbon fibre fabric having continuous fibres. The fabric has a weight of about 250 g/m² with an orientation of 0°/90°. The fibre composite material sheets were produced in a pressing process.

A powder coating H1 composed of a copolyamide-based hotmelt adhesive (Vestamelt X1333-P1 from Evonik) comprising an epoxy component and a blocked polyisocyanate was applied to a composite partner composed of fiber composite material.

The powder coating was applied electrostatically with a layer thickness of 50-70 μm and stoved at 160° C. for 5 min. For this purpose, the coated metal sheets were placed in a preheated autoclave (oven).

After the stoving procedure, guillotine shears were used to cut the coated and uncoated fibre composite materials into strips appropriate for the pressing operation with dimensions of 60.0 mm×25.0 mm (tolerance+0−0.2 mm).

The bond between coated plastic and fibre composite material was obtained by a pressing operation in a hydraulic hot press (manufacturer: Paul Weber, name: TEMPRESS). This is done by inserting the coated fibre composite material into a template in one half of the hot press. A sheet of an uncoated fibre composite material is positioned thereon. Before the joining operation, the press is heated to about 230° C. Thereafter, the coated fibre composite material and the uncoated fibre composite material are pressed at a pressure of about 32 bar with a hold time of about 5 min to give a composite body. The region of overlap was about 25 mm×25 mm. The test sample had a total length of about 130 mm.

The test samples thus produced were stored at 50% relative humidity for at least 24 h at 23° C. in order to ensure a uniform state of conditioning. The test samples are then clamped into a standard Zwick/Roell Z-020 tensile tester and tested with a velocity of 5 mm/min at 23° C. with a distance between the clamps and the overlap region of about 15 mm/side.

Fibre Fibre composite Adhesion composite Adhesion in Example material promoter material MPa 69 C1 without C2 2.9 70 C1 H1 C2 7.7 71 C1 without C3 8.8 72 C1 H1 C3 11.0 73 C4 without C5 n.r. 74 C4 H1 C5 13.0 75 C1 without C5 11.0 76 C1 H1 C5 15.0 *inventive; n.r.: no result; n.m. = not measurable: (no adhesion) 

1. A hybrid component comprising: at least one fibre composite material as material B, and at least one material A, wherein material A is selected from the group consisting of plastics, metals, ceramic compositions, wood, glass, composite materials, textile fibres and prefabricated products produced from textile fibres, and wherein material A is bonded to material B by at least one coating of an adhesion promoter composition containing at least one copolyamide-based hotmelt adhesive.
 2. The hybrid component according to claim 1, wherein the fibre composite material of material B is a fibre-plastic composite.
 3. The hybrid component according to claim 2, wherein the fibres of the fibre-plastic composite are selected from the group consisting of carbon fibres and glass fibres.
 4. The hybrid component according to claim 1, wherein material A is selected from the group consisting of plastics, metals and fibre composite materials.
 5. The hybrid component according to claim 1, wherein the hybrid component further comprises at least one material C selected from the group consisting of plastics, metals, ceramic compositions, wood, glass, composite materials, textile fibres and prefabricated products produced from textile fibres.
 6. A process for producing a hybrid component according to claim 1, wherein the adhesion promoter composition is at least partly applied to or laid onto material A, material B or both materials, and materials A and B are bonded to one another.
 7. The process according to claim 6, wherein a material C is applied to or laid onto the hybrid component and material C is bonded to the hybrid component.
 8. The process according to claim 6, wherein a material C is bonded to materials A and B together.
 9. A structural component, lightweight component, component having a surface function or protective function, or as decorative component that comprises the hybrid component according to claim
 1. 10. A method for producing a hybrid component according to claim 1 comprising applying at least one copolyamide-based hotmelt adhesive as an adhesion promoter between a fibre composite material B and a material A. 